/*
 * FreeRTOS Kernel V10.5.1
 * Copyright (C) 2021 Amazon.com, Inc. or its affiliates.  All Rights Reserved.
 *
 * SPDX-License-Identifier: MIT
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of
 * this software and associated documentation files (the "Software"), to deal in
 * the Software without restriction, including without limitation the rights to
 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
 * the Software, and to permit persons to whom the Software is furnished to do so,
 * subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
 * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
 * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 * https://www.FreeRTOS.org
 * https://github.com/FreeRTOS
 *
 */

/*
 * A sample implementation of pvPortMalloc() that allows the heap to be defined
 * across multiple non-contigous blocks and combines (coalescences) adjacent
 * memory blocks as they are freed.
 *
 * See heap_1.c, heap_2.c, heap_3.c and heap_4.c for alternative
 * implementations, and the memory management pages of https://www.FreeRTOS.org
 * for more information.
 *
 * Usage notes:
 *
 * vPortDefineHeapRegions() ***must*** be called before pvPortMalloc().
 * pvPortMalloc() will be called if any task objects (tasks, queues, event
 * groups, etc.) are created, therefore vPortDefineHeapRegions() ***must*** be
 * called before any other objects are defined.
 *
 * vPortDefineHeapRegions() takes a single parameter.  The parameter is an array
 * of HeapRegion_t structures.  HeapRegion_t is defined in portable.h as
 *
 * typedef struct HeapRegion
 * {
 *  uint8_t *pucStartAddress; << Start address of a block of memory that will be part of the heap.
 *  size_t xSizeInBytes;      << Size of the block of memory.
 * } HeapRegion_t;
 *
 * The array is terminated using a NULL zero sized region definition, and the
 * memory regions defined in the array ***must*** appear in address order from
 * low address to high address.  So the following is a valid example of how
 * to use the function.
 *
 * HeapRegion_t xHeapRegions[] =
 * {
 *  { ( uint8_t * ) 0x80000000UL, 0x10000 }, << Defines a block of 0x10000 bytes starting at address 0x80000000
 *  { ( uint8_t * ) 0x90000000UL, 0xa0000 }, << Defines a block of 0xa0000 bytes starting at address of 0x90000000
 *  { NULL, 0 }                << Terminates the array.
 * };
 *
 * vPortDefineHeapRegions( xHeapRegions ); << Pass the array into vPortDefineHeapRegions().
 *
 * Note 0x80000000 is the lower address so appears in the array first.
 *
 */
#include <stdlib.h>
#include <string.h>

/* Defining MPU_WRAPPERS_INCLUDED_FROM_API_FILE prevents task.h from redefining
 * all the API functions to use the MPU wrappers.  That should only be done when
 * task.h is included from an application file. */
#define MPU_WRAPPERS_INCLUDED_FROM_API_FILE

#include "FreeRTOS.h"
#include "task.h"

#undef MPU_WRAPPERS_INCLUDED_FROM_API_FILE

#if (configSUPPORT_DYNAMIC_ALLOCATION == 0)
    #error This file must not be used if configSUPPORT_DYNAMIC_ALLOCATION is 0
#endif

#ifndef configHEAP_CLEAR_MEMORY_ON_FREE
    #define configHEAP_CLEAR_MEMORY_ON_FREE 0
#endif

/* Block sizes must not get too small. */
#define heapMINIMUM_BLOCK_SIZE ((size_t)(xHeapStructSize << 1))

/* Assumes 8bit bytes! */
#define heapBITS_PER_BYTE ((size_t)8)

/* Max value that fits in a size_t type. */
#define heapSIZE_MAX (~((size_t)0))

/* Check if multiplying a and b will result in overflow. */
#define heapMULTIPLY_WILL_OVERFLOW(a, b) (((a) > 0) && ((b) > (heapSIZE_MAX / (a))))

/* Check if adding a and b will result in overflow. */
#define heapADD_WILL_OVERFLOW(a, b) ((a) > (heapSIZE_MAX - (b)))

/* MSB of the xBlockSize member of an BlockLink_t structure is used to track
 * the allocation status of a block.  When MSB of the xBlockSize member of
 * an BlockLink_t structure is set then the block belongs to the application.
 * When the bit is free the block is still part of the free heap space. */
#define heapBLOCK_ALLOCATED_BITMASK         (((size_t)1) << ((sizeof(size_t) * heapBITS_PER_BYTE) - 1))
#define heapBLOCK_SIZE_IS_VALID(xBlockSize) (((xBlockSize)&heapBLOCK_ALLOCATED_BITMASK) == 0)
#define heapBLOCK_IS_ALLOCATED(pxBlock)     (((pxBlock->xBlockSize) & heapBLOCK_ALLOCATED_BITMASK) != 0)
#define heapALLOCATE_BLOCK(pxBlock)         ((pxBlock->xBlockSize) |= heapBLOCK_ALLOCATED_BITMASK)
#define heapFREE_BLOCK(pxBlock)             ((pxBlock->xBlockSize) &= ~heapBLOCK_ALLOCATED_BITMASK)

/*-----------------------------------------------------------*/

/* Define the linked list structure.  This is used to link free blocks in order
 * of their memory address. */
typedef struct A_BLOCK_LINK {
    struct A_BLOCK_LINK *pxNextFreeBlock; /*<< The next free block in the list. */
    size_t xBlockSize; /*<< The size of the free block. */
} BlockLink_t;

/*-----------------------------------------------------------*/

/*
 * Inserts a block of memory that is being freed into the correct position in
 * the list of free memory blocks.  The block being freed will be merged with
 * the block in front it and/or the block behind it if the memory blocks are
 * adjacent to each other.
 */
static void prvInsertBlockIntoFreeList(BlockLink_t *pxBlockToInsert);

/*-----------------------------------------------------------*/

/* The size of the structure placed at the beginning of each allocated memory
 * block must by correctly byte aligned. */
static const size_t xHeapStructSize = (sizeof(BlockLink_t) + ((size_t)(portBYTE_ALIGNMENT - 1))) & ~((size_t)portBYTE_ALIGNMENT_MASK);

/* Create a couple of list links to mark the start and end of the list. */
static BlockLink_t xStart;
static BlockLink_t *pxEnd = NULL;

/* Keeps track of the number of calls to allocate and free memory as well as the
 * number of free bytes remaining, but says nothing about fragmentation. */
static size_t xFreeBytesRemaining = 0U;
static size_t xMinimumEverFreeBytesRemaining = 0U;
static size_t xNumberOfSuccessfulAllocations = 0;
static size_t xNumberOfSuccessfulFrees = 0;

/*-----------------------------------------------------------*/

void *pvPortMalloc(size_t xWantedSize) {
    BlockLink_t *pxBlock;
    BlockLink_t *pxPreviousBlock;
    BlockLink_t *pxNewBlockLink;
    void *pvReturn = NULL;
    size_t xAdditionalRequiredSize;

    /* The heap must be initialised before the first call to
     * prvPortMalloc(). */
    configASSERT(pxEnd);

    vTaskSuspendAll();
    {
        if (xWantedSize > 0) {
            /* The wanted size must be increased so it can contain a BlockLink_t
             * structure in addition to the requested amount of bytes. Some
             * additional increment may also be needed for alignment. */
            xAdditionalRequiredSize = xHeapStructSize + portBYTE_ALIGNMENT - (xWantedSize & portBYTE_ALIGNMENT_MASK);

            if (heapADD_WILL_OVERFLOW(xWantedSize, xAdditionalRequiredSize) == 0) {
                xWantedSize += xAdditionalRequiredSize;
            } else {
                xWantedSize = 0;
            }
        } else {
            mtCOVERAGE_TEST_MARKER();
        }

        /* Check the block size we are trying to allocate is not so large that the
         * top bit is set.  The top bit of the block size member of the BlockLink_t
         * structure is used to determine who owns the block - the application or
         * the kernel, so it must be free. */
        if (heapBLOCK_SIZE_IS_VALID(xWantedSize) != 0) {
            if ((xWantedSize > 0) && (xWantedSize <= xFreeBytesRemaining)) {
                /* Traverse the list from the start (lowest address) block until
                 * one of adequate size is found. */
                pxPreviousBlock = &xStart;
                pxBlock = xStart.pxNextFreeBlock;

                while ((pxBlock->xBlockSize < xWantedSize) && (pxBlock->pxNextFreeBlock != NULL)) {
                    pxPreviousBlock = pxBlock;
                    pxBlock = pxBlock->pxNextFreeBlock;
                }

                /* If the end marker was reached then a block of adequate size
                 * was not found. */
                if (pxBlock != pxEnd) {
                    /* Return the memory space pointed to - jumping over the
                     * BlockLink_t structure at its start. */
                    pvReturn = (void *)(((uint8_t *)pxPreviousBlock->pxNextFreeBlock) + xHeapStructSize);

                    /* This block is being returned for use so must be taken out
                     * of the list of free blocks. */
                    pxPreviousBlock->pxNextFreeBlock = pxBlock->pxNextFreeBlock;

                    /* If the block is larger than required it can be split into
                     * two. */
                    if ((pxBlock->xBlockSize - xWantedSize) > heapMINIMUM_BLOCK_SIZE) {
                        /* This block is to be split into two.  Create a new
                         * block following the number of bytes requested. The void
                         * cast is used to prevent byte alignment warnings from the
                         * compiler. */
                        pxNewBlockLink = (void *)(((uint8_t *)pxBlock) + xWantedSize);

                        /* Calculate the sizes of two blocks split from the
                         * single block. */
                        pxNewBlockLink->xBlockSize = pxBlock->xBlockSize - xWantedSize;
                        pxBlock->xBlockSize = xWantedSize;

                        /* Insert the new block into the list of free blocks. */
                        prvInsertBlockIntoFreeList((pxNewBlockLink));
                    } else {
                        mtCOVERAGE_TEST_MARKER();
                    }

                    xFreeBytesRemaining -= pxBlock->xBlockSize;

                    if (xFreeBytesRemaining < xMinimumEverFreeBytesRemaining) {
                        xMinimumEverFreeBytesRemaining = xFreeBytesRemaining;
                    } else {
                        mtCOVERAGE_TEST_MARKER();
                    }

                    /* The block is being returned - it is allocated and owned
                     * by the application and has no "next" block. */
                    heapALLOCATE_BLOCK(pxBlock);
                    pxBlock->pxNextFreeBlock = NULL;
                    xNumberOfSuccessfulAllocations++;
                } else {
                    mtCOVERAGE_TEST_MARKER();
                }
            } else {
                mtCOVERAGE_TEST_MARKER();
            }
        } else {
            mtCOVERAGE_TEST_MARKER();
        }

        traceMALLOC(pvReturn, xWantedSize);
    }
    (void)xTaskResumeAll();

#if (configUSE_MALLOC_FAILED_HOOK == 1)
    {
        if (pvReturn == NULL) {
            vApplicationMallocFailedHook();
        } else {
            mtCOVERAGE_TEST_MARKER();
        }
    }
#endif /* if ( configUSE_MALLOC_FAILED_HOOK == 1 ) */

    return pvReturn;
}
/*-----------------------------------------------------------*/

void vPortFree(void *pv) {
    uint8_t *puc = (uint8_t *)pv;
    BlockLink_t *pxLink;

    if (pv != NULL) {
        /* The memory being freed will have an BlockLink_t structure immediately
         * before it. */
        puc -= xHeapStructSize;

        /* This casting is to keep the compiler from issuing warnings. */
        pxLink = (void *)puc;

        configASSERT(heapBLOCK_IS_ALLOCATED(pxLink) != 0);
        configASSERT(pxLink->pxNextFreeBlock == NULL);

        if (heapBLOCK_IS_ALLOCATED(pxLink) != 0) {
            if (pxLink->pxNextFreeBlock == NULL) {
                /* The block is being returned to the heap - it is no longer
                 * allocated. */
                heapFREE_BLOCK(pxLink);
#if (configHEAP_CLEAR_MEMORY_ON_FREE == 1)
                {
                    (void)memset(puc + xHeapStructSize, 0, pxLink->xBlockSize - xHeapStructSize);
                }
#endif

                vTaskSuspendAll();
                {
                    /* Add this block to the list of free blocks. */
                    xFreeBytesRemaining += pxLink->xBlockSize;
                    traceFREE(pv, pxLink->xBlockSize);
                    prvInsertBlockIntoFreeList(((BlockLink_t *)pxLink));
                    xNumberOfSuccessfulFrees++;
                }
                (void)xTaskResumeAll();
            } else {
                mtCOVERAGE_TEST_MARKER();
            }
        } else {
            mtCOVERAGE_TEST_MARKER();
        }
    }
}
/*-----------------------------------------------------------*/

size_t xPortGetFreeHeapSize(void) {
    return xFreeBytesRemaining;
}
/*-----------------------------------------------------------*/

size_t xPortGetMinimumEverFreeHeapSize(void) {
    return xMinimumEverFreeBytesRemaining;
}
/*-----------------------------------------------------------*/

void *pvPortCalloc(size_t xNum,
    size_t xSize) {
    void *pv = NULL;

    if (heapMULTIPLY_WILL_OVERFLOW(xNum, xSize) == 0) {
        pv = pvPortMalloc(xNum * xSize);

        if (pv != NULL) {
            (void)memset(pv, 0, xNum * xSize);
        }
    }

    return pv;
}
/*-----------------------------------------------------------*/

static void prvInsertBlockIntoFreeList(BlockLink_t *pxBlockToInsert) {
    BlockLink_t *pxIterator;
    uint8_t *puc;

    /* Iterate through the list until a block is found that has a higher address
     * than the block being inserted. */
    for (pxIterator = &xStart; pxIterator->pxNextFreeBlock < pxBlockToInsert; pxIterator = pxIterator->pxNextFreeBlock) {
        /* Nothing to do here, just iterate to the right position. */
    }

    /* Do the block being inserted, and the block it is being inserted after
     * make a contiguous block of memory? */
    puc = (uint8_t *)pxIterator;

    if ((puc + pxIterator->xBlockSize) == (uint8_t *)pxBlockToInsert) {
        pxIterator->xBlockSize += pxBlockToInsert->xBlockSize;
        pxBlockToInsert = pxIterator;
    } else {
        mtCOVERAGE_TEST_MARKER();
    }

    /* Do the block being inserted, and the block it is being inserted before
     * make a contiguous block of memory? */
    puc = (uint8_t *)pxBlockToInsert;

    if ((puc + pxBlockToInsert->xBlockSize) == (uint8_t *)pxIterator->pxNextFreeBlock) {
        if (pxIterator->pxNextFreeBlock != pxEnd) {
            /* Form one big block from the two blocks. */
            pxBlockToInsert->xBlockSize += pxIterator->pxNextFreeBlock->xBlockSize;
            pxBlockToInsert->pxNextFreeBlock = pxIterator->pxNextFreeBlock->pxNextFreeBlock;
        } else {
            pxBlockToInsert->pxNextFreeBlock = pxEnd;
        }
    } else {
        pxBlockToInsert->pxNextFreeBlock = pxIterator->pxNextFreeBlock;
    }

    /* If the block being inserted plugged a gab, so was merged with the block
     * before and the block after, then it's pxNextFreeBlock pointer will have
     * already been set, and should not be set here as that would make it point
     * to itself. */
    if (pxIterator != pxBlockToInsert) {
        pxIterator->pxNextFreeBlock = pxBlockToInsert;
    } else {
        mtCOVERAGE_TEST_MARKER();
    }
}
/*-----------------------------------------------------------*/

void vPortDefineHeapRegions(const HeapRegion_t *const pxHeapRegions) {
    BlockLink_t *pxFirstFreeBlockInRegion = NULL;
    BlockLink_t *pxPreviousFreeBlock;
    portPOINTER_SIZE_TYPE xAlignedHeap;
    size_t xTotalRegionSize, xTotalHeapSize = 0;
    BaseType_t xDefinedRegions = 0;
    portPOINTER_SIZE_TYPE xAddress;
    const HeapRegion_t *pxHeapRegion;

    /* Can only call once! */
    configASSERT(pxEnd == NULL);

    pxHeapRegion = &(pxHeapRegions[xDefinedRegions]);

    while (pxHeapRegion->xSizeInBytes > 0) {
        xTotalRegionSize = pxHeapRegion->xSizeInBytes;

        /* Ensure the heap region starts on a correctly aligned boundary. */
        xAddress = (portPOINTER_SIZE_TYPE)pxHeapRegion->pucStartAddress;

        if ((xAddress & portBYTE_ALIGNMENT_MASK) != 0) {
            xAddress += (portBYTE_ALIGNMENT - 1);
            xAddress &= ~portBYTE_ALIGNMENT_MASK;

            /* Adjust the size for the bytes lost to alignment. */
            xTotalRegionSize -= (size_t)(xAddress - (portPOINTER_SIZE_TYPE)pxHeapRegion->pucStartAddress);
        }

        xAlignedHeap = xAddress;

        /* Set xStart if it has not already been set. */
        if (xDefinedRegions == 0) {
            /* xStart is used to hold a pointer to the first item in the list of
             *  free blocks.  The void cast is used to prevent compiler warnings. */
            xStart.pxNextFreeBlock = (BlockLink_t *)xAlignedHeap;
            xStart.xBlockSize = (size_t)0;
        } else {
            /* Should only get here if one region has already been added to the
             * heap. */
            configASSERT(pxEnd != NULL);

            /* Check blocks are passed in with increasing start addresses. */
            configASSERT(xAddress > (size_t)pxEnd);
        }

        /* Remember the location of the end marker in the previous region, if
         * any. */
        pxPreviousFreeBlock = pxEnd;

        /* pxEnd is used to mark the end of the list of free blocks and is
         * inserted at the end of the region space. */
        xAddress = xAlignedHeap + xTotalRegionSize;
        xAddress -= xHeapStructSize;
        xAddress &= ~((size_t)portBYTE_ALIGNMENT_MASK);
        pxEnd = (BlockLink_t *)xAddress;
        pxEnd->xBlockSize = 0;
        pxEnd->pxNextFreeBlock = NULL;

        /* To start with there is a single free block in this region that is
         * sized to take up the entire heap region minus the space taken by the
         * free block structure. */
        pxFirstFreeBlockInRegion = (BlockLink_t *)xAlignedHeap;
        pxFirstFreeBlockInRegion->xBlockSize = (size_t)(xAddress - (portPOINTER_SIZE_TYPE)pxFirstFreeBlockInRegion);
        pxFirstFreeBlockInRegion->pxNextFreeBlock = pxEnd;

        /* If this is not the first region that makes up the entire heap space
         * then link the previous region to this region. */
        if (pxPreviousFreeBlock != NULL) {
            pxPreviousFreeBlock->pxNextFreeBlock = pxFirstFreeBlockInRegion;
        }

        xTotalHeapSize += pxFirstFreeBlockInRegion->xBlockSize;

        /* Move onto the next HeapRegion_t structure. */
        xDefinedRegions++;
        pxHeapRegion = &(pxHeapRegions[xDefinedRegions]);
    }

    xMinimumEverFreeBytesRemaining = xTotalHeapSize;
    xFreeBytesRemaining = xTotalHeapSize;

    /* Check something was actually defined before it is accessed. */
    configASSERT(xTotalHeapSize);
}
/*-----------------------------------------------------------*/

void vPortGetHeapStats(HeapStats_t *pxHeapStats) {
    BlockLink_t *pxBlock;
    size_t xBlocks = 0, xMaxSize = 0, xMinSize = portMAX_DELAY; /* portMAX_DELAY used as a portable way of getting the maximum value. */

    vTaskSuspendAll();
    {
        pxBlock = xStart.pxNextFreeBlock;

        /* pxBlock will be NULL if the heap has not been initialised.  The heap
         * is initialised automatically when the first allocation is made. */
        if (pxBlock != NULL) {
            while (pxBlock != pxEnd) {
                /* Increment the number of blocks and record the largest block seen
                 * so far. */
                xBlocks++;

                if (pxBlock->xBlockSize > xMaxSize) {
                    xMaxSize = pxBlock->xBlockSize;
                }

                /* Heap five will have a zero sized block at the end of each
                 * each region - the block is only used to link to the next
                 * heap region so it not a real block. */
                if (pxBlock->xBlockSize != 0) {
                    if (pxBlock->xBlockSize < xMinSize) {
                        xMinSize = pxBlock->xBlockSize;
                    }
                }

                /* Move to the next block in the chain until the last block is
                 * reached. */
                pxBlock = pxBlock->pxNextFreeBlock;
            }
        }
    }
    (void)xTaskResumeAll();

    pxHeapStats->xSizeOfLargestFreeBlockInBytes = xMaxSize;
    pxHeapStats->xSizeOfSmallestFreeBlockInBytes = xMinSize;
    pxHeapStats->xNumberOfFreeBlocks = xBlocks;

    taskENTER_CRITICAL();
    {
        pxHeapStats->xAvailableHeapSpaceInBytes = xFreeBytesRemaining;
        pxHeapStats->xNumberOfSuccessfulAllocations = xNumberOfSuccessfulAllocations;
        pxHeapStats->xNumberOfSuccessfulFrees = xNumberOfSuccessfulFrees;
        pxHeapStats->xMinimumEverFreeBytesRemaining = xMinimumEverFreeBytesRemaining;
    }
    taskEXIT_CRITICAL();
}
/*-----------------------------------------------------------*/
